“I can't see clearly, because I don't wear my glasses today.” We always hear people saying something like this. Glasses are very important to many people. Do you know how they were invented and developed?

    Glasses took a long time to develop into what you can find in the glasses store today. The Chinese first used colored glasses as fashion. They thought that those glasses had magic, but they didn't think that glasses could help eyes to see clearly.

    In 1262, the inventor, Roger Bacon, discovered the amazing function(功能) of lenses(镜片), and he thought that glasses could be used to help people to see. Twenty years later, in Florence, Italy, the inventor, Alessandro di Spina, made the first pair of glasses that could help people to see.

Although these glasses worked, scientists didn't understand how glasses helped eyes to see. They thought that eyes sent out light onto whatever a person was looking at, and then the light came back to the eyes. Johannes Kepler finally found out how glasses worked.

Inventors continued to improve glasses. In 1784, Ben Franklin created glasses that had bifocal(双焦的) lenses. Many years later, in 1827, George Airy made circle-shaped glasses to correct astigmatism, an eye problem that stops the eyes from seeing things clearly.

    Canada is the second largest country in the world. It is over 7，000 kilometers from the 1 coast（海岸）to the east. It 2 six time zones. 3 it is 9 a. m. in Vancouver on the west coast，it is 1：30 p.m. in St John's on the east coast.

    English and French 4 the two main languages in Canada. About 60 percent of 5 people speak English， and about 25 percent speak French. More 6 70 percent of its population live in cities near the US border（边境）.

    Ottawa is the capital. Every year millions of tourists go there to7 museums and take part in the cultural（文化的）activities. Toronto is the largest city of the country 8 about 2. 5 million people. Montreal is 9 second biggest French-speaking city in the world.

    The maple leaf is the national symbol of Canada. The Canadian flag has a red maple leaf on a red 10 white background.

    Americans are very direct people. When they want something they say "yes" and when they don't they say "no". If they want something different from what is given, they ask for it. Here's an example. I arrive at someone's house and he gives me wine, I don't want wine. Maybe I don't like it or maybe I just don't want it. I will say "No, thanks." If everyone around me is drinking something, I would ask for something else, "No, thanks. But I'll take a bit of tea if you have some." If I really want wine, I just say, "Yes, thank you." Unless they happen to know the Chinese customs, westerners will not ask you again and again after you have said you don't want it.